Zoisite has a complex chemical structure. It contains single silicate tetrahedrons, SiO₄, and double silicate tetrahedrons, Si₂O₇. This chemical composition is characteristic of all rocks which are known under generic name of epidote. Other members of epidote group are: clinozoisite, epidote per se, piemontite, and allanite. Zoisite takes its name from its discoverer - Siegmund Zois, Baron von Edelstein (1747-1819), who supplied the the first specimens

Zoisite is mainly found in in medium-grade regionally metamorphosed crystalline schists formed from igneous, sedimentary, or metamorphic rocks relatively high in calcium. It is frequently associated with albite, andradite, biotite, calcite, corundum, garnet and quartz. The main sources of Zoisite come from Tanzania, USA, Switzerland, India and Austria.

Zoisite varieties

Anyolite

Anylite is often referred to as Ruby-Zoisite. It is a gem-rock variety consisting of apple-green Zoisite and Ruby-red Corundum. Ruby-Zoisite is unusual because of marked differences of hardness of its chief constituents (Ziosite - 6.5; Corundum - 9) which in turn suggests that the fusion between these two rocks is difficult. The name Anylite apparently comes from the Masai (of Tanzania) word for green.

 

Mineral uses

• for ornamental stonework
• for jewellery (especially Tanzanite, but also Thulite)
• as a jade substitute
• as a collector's mineral